Lin Shen, a new prison guard at Nanzhou No. 3 Psychiatric Prison, unexpectedly received a "prisoner's true identity device" (an old mobile phone engraved with his father's police number) on the day he entered the job. He could see the prisoner's hidden true identity and undisclosed crimes. He discovered that the "crazy prisoners" in the prison were not really mentally abnormal, but "troublesome people" deliberately imprisoned by the hypocritical prison warden Zhou Mingyuan. Some were witnesses with evidence of criminal groups, and some were members of betrayal groups. On the surface, Lin Shen pretends to be a "good-for-nothing prison guard", but in fact, he uses his golden fingers to collect evidence, gradually revealing Zhou Mingyuan's true identity as the mastermind behind the "Scavenger" criminal group. In the process, he engages in many psychological games with Zhou Mingyuan, and finally wipes out the criminal group and clears his father (a former criminal police captain who was wrongly accused and died while investigating the group).
